1. Field of the Invention
The present invention relates to a liquid crystal display device.
2. Description of the Related Art
FIG. 19 is a diagram showing a general liquid crystal display device 100. As shown in the diagram, the liquid crystal display device 100 mainly comprises a liquid crystal panel 102, a data line driving circuit 104, and a scan line driving circuit 106. Further, a data line DL vertically extending, a scan line GL horizontally extending, and a common line CL formed over common electrodes are formed on the liquid crystal panel 102, as shown in the enlarged diagram. Still further, as shown in the enlarged diagram, a TFT transistor TR, a pixel electrode, and a common electrode are formed in the pixel area enclosed by the data line DL and the scan line GL. Yet further, the pixel area additionally has parasitic capacitance Cgs between the gate and drain of the TFT transistor TR, pixel capacitance Clc between the pixel electrode and the common electrode, and auxiliary capacitance Cst.
The scan line driving circuit 106 selects the scan line GL, beginning with the one at the top, and outputs a scan signal to the selected scan line GL during one horizontal period. Meanwhile, the data line driving circuit 104 outputs a video signal to each data line DL for every selection of the scan line GL by the scan driving circuit 106.
In the above described liquid crystal display device 100, presence of the parasitic capacitance Cgs causes a field through phenomenon in which the voltage of the pixel electrode falls upon a fall of the voltage of the scan signal. FIG. 20 shows a field through phenomenon. As shown in the diagram, upon a fall of the scan signal, the voltage of a pixel electrode falls by an amount “Δ”.
It has been known that because the symmetric property between the positive polarity voltage and the negative polarity voltage of a pixel electrode relative to the common voltage Vc is destroyed due to the field through phenomenon, as shown in FIG. 21, despite employment of a frame inversion method, such as a column line inversion driving method, a dot inversion driving method, and the like, in the liquid crystal display device 100, the pixel is charged with a DC charge, which consequently causes a defect of a so-called afterimage (or burn-in).
In view of the above, in a liquid crystal display device described in WO2009/133906A1, in order to avoid imbalance in polarity of the voltage of a pixel electrode into one polarity, the video signal output from the data line DC is corrected so that video signal at a higher voltage than usual is output (see FIG. 22). Further, according to WO2009/133906A1, considering that the amount Δ will change depending on the horizontal position of the pixel, the amount of correction to a video signal is adjusted according to the horizontal position of the pixel.